This application claims the priority of Korean Patent Application No. 10-2003-0052052 filed on Jul. 28, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of Invention
The present invention relates to data transmission and reception using a transport layer of the 7 layers of Open System Interconnection (OSI), and more particularly, to a method of efficiently transmitting/receiving data using a transmission control protocol (TCP) of a transport layer in a mobile ad hoc network environment.
2. Description of the Prior Art
In a mobile ad hoc network environment that adopts IEEE 802.11, all nodes share a communication channel. Therefore, since all nodes present in the same communication coverage area communicate over the same channel, it is likely that transmitted data will collide with one another or be lost. Further, the characteristics of a wireless network adversely affect the transmission reliability of link layers. To overcome such drawbacks, there has been proposed a scheme for attempting to achieve reliable data transmission by using TCP at the transport layer level.
FIG. 1 is an exemplary view illustrating TCP operations in the related art, wherein a sending party sends packets to a receiving party that in turn sends the sending party ACK-response packets in response to the packets received from the sending party. At this time, the receiving party sends the ACK-response packets while maintaining the maximum value of sequence numbers of successive packets that have been received from the sending party, so that transmission amounts by the sending party cannot be reduced even though some of the ACK-response packets such as 2′ACK-response packet are lost.
TCP is a protocol for the transport layer in a TCP/IP architecture and is mainly responsible for the control of data flow and error. In particular, TCP adopts the concept of a “window” for the control of data flow, whereby only the amount of data corresponding to the size of a window is sent when data to be transmitted have been stored in a buffer by means of an application program. At this time, the size of the window is determined depending on a destination host or network congestion and thus can be increased or decreased. Particularly, TCP adopts a sliding window technique. With the use of such concept of a window, the utilization of wireless links can be maximized.
However, since TCP usually generates ACK-response packets for most of the incoming packets, channel competition of the ACK-response packets with data packets may occur. Further, in a wireless environment adopting a Request to Send/Clear to Send (RTS/CTS) scheme, the utilization of channels in a wireless network may be greatly reduced due to ACK-response packets. Therefore, to overcome such drawbacks, there exists a need for decrease in the number of ACK-response packets.